Fluorescence imaging is employed for imaging subcutaneous tissues. The fluorescence imager detects fluorescence light emitted from a fluorescence agent that is excited by appropriate illumination. For example, a fluorescent endoscope is an imaging system for imaging internal blood flow, visible through tissue, by promoting fluorescence radiation from a fluorescent dye added to the flowing blood. The endoscope can be employed, for example, during surgery for visualizing the blood flow, and for evaluating tissue perfusion and vessel patency.
Light guides for providing excitation illumination to fluorescence imaging systems are known in the art. Reference is now made to EP Patent Application Publication Number EP2502549A1, to Koji et al., and entitled “Endoscope Apparatus”. This publication describes an endoscope having a light guiding portion that guides the light output from a light source (i.e., fluorescence excitation light source). The light guiding portion is equipped with a diffusing portion at the output end thereof. The diffuser is designed to diffuse the output excitation light for preventing the light from causing damage to the eye of the user.
Reference is now made to a light shaping diffusers technical data sheet of Luminit Co. This publication describes a diffuser that modifies the angular output of an incoming light beam in accordance with the angular output of the incoming light beam in accordance with the angular output of the incoming beam and with the diffuser angle.
Reference is now made to US Patent Application Publication Number 2013/0060087 to Yoshida, and entitled “Rigid Scope Apparatus”. This publication is directed at a rigid scope apparatus including an illumination fiber. The illumination fiber contains a white light fiber bundle and a near infrared fiber bundle. The white light fiber bundle and the near infrared fiber bundle can be concentrically formed within the illumination fiber. The rigid scope apparatus may further include a white light diffusion section for diffusing the white light, and an infrared diffusion section for diffusing the near infrared light.